The present invention relates to arrangements for handling cassettes in general, and more particularly to an arrangement for loading and unloading X-ray film cassettes.
There is already known, from the German published patent application DE-OS No. 26 07 876 an arrangement for unloading and loading X-ray film cassettes, which includes a channel for the accommodation of the respective X-ray film cassette, transporting elements for displacing the cassette into and out of the channel, a closure for a light-impervious closing of the inlet opening of the channel, an arrangement for opening the respective cassette while in the channel and while the closure is closed, and an arrangement for removing X-ray films from the cassettes and introducing different X-ray films into the cassettes. In this construction, the transporting elements are constituted by endless conveyor belts or bands, which move the respective cassette all the way into the channel, until the cassette abuts an abutment in which there is provided a microswitch which terminates the operation of the drive of the transporting elements. A pair of rubber rollers is arranged at the inlet opening. These rubber rollers, on the one hand, receive the respective cassette between themselves and guide the same toward the transporting elements and, on the other hand, cooperate with two additional rollers to constitute the light-impervious or light-tight closure for the inlet opening and thus for the channel. These four entrance rollers are relatively expensive. Moreover, and possibly more importantly, the rubber rollers must be frequently replaced, since a deformation of their peripheral surfaces due to the contact with the cassettes, which have substantial dimensions and particularly thicknesses, occurs after a relatively short period of use. Once this damage or deformation occurs, the light-tight closing action of the closure cannot be assured any longer. An additional disadvantage which was found to exist in this conventional construction and which is also of a considerable importance is that, during the discharge of the cassette from the channel following the termination of the loading and unloading operation, the cassette has to be held between the rubber rollers for a considerable period of time when a depositing table arranged externally at the inlet opening of the arrangement has a short length, which results in a further deformation of the rubber rollers, or, should it be preferred that the cassette be fully discharged from the channel and deposited on the depositing table, the latter must be so dimensioned as to be able to support the cassette having the largest dimensions. It is well known that the X-ray film cassettes have dimensions which vary from one another in a wide range, depending on the dimensions of the X-ray films which, in turn, depend on the dimensions of the body part to be X-rayed and the construction of the X-ray machine. Thus, the relatively expensive large-dimension depositing table will be underutilized most of the time, and the arrangement with the table will occupy more space than necessary.